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Proceedings Paper

Efficient particle trapping using an upward reflected laser beam
Author(s): Alexandr Jonas; Libor Sramek; Miroslav Liska; Pavel Zemanek
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Paper Abstract

We suggest a modification of a single-beam optical trap built in a conventional microscope (not the inverted one). Our enhancement of the trapping efficiency consists of a highly-reflective-layers-coated glass plate forming the bottom of the sample cell. Using this, we obtain a combination of two beams--the incident one propagating downward and the reflected one propagating upward--which together create an effective microobject trap. Using the micron-size polystyrene spheres we have experimentally proved that it is easy to achieve an efficient 3D trapping using even highly aberrated beams although the single beam trap does not work in this case. The interference of the incident and reflected beams forms a standing wave which is especially useful for nanoobjects trapping. Nanoobjects of diameters equal to tens of nanometers are stably trapped near the antinodes (intensity maxima) of the standing wave due to the restoring dipole force which is thousands times greater than the scattering force in this case. The paper presents the qualitative description of the trapped object behavior, theoretical study and calculations of forces acting on the microobjects and nanoobjects. The influence of the standing wave on the observed microsphere behavior is also discussed.

Paper Details

Date Published: 6 November 1998
PDF: 11 pages
Proc. SPIE 3580, Photoconversion: Science and Technologies, (6 November 1998); doi: 10.1117/12.330439
Show Author Affiliations
Alexandr Jonas, Technical Univ. of Brno (Czech Republic)
Libor Sramek, Technical Univ. of Brno (Czech Republic)
Miroslav Liska, Technical Univ. of Brno (Czech Republic)
Pavel Zemanek, Institute of Scientific Instruments (Czech Republic)

Published in SPIE Proceedings Vol. 3580:
Photoconversion: Science and Technologies
Maksymilian Pluta; Mariusz Szyjer, Editor(s)

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